High bulk continuous filament low stretch yarn



P 1968 R. w. CHIDGEY ETAL 3,401,516

HIGH BULK CONTINUOUS FILAMENT LOW STRETCH YARN Filed May 31. 1966INVENTORS RONALD W. CHIDGEY WILLIAM H. HILLS 1% 'm. lint ATTORNEY UnitedStates Patent 3,401,516 HIGH BULK CONTINUOUS FILAMENT LOW STRETCH YARNRonald W. Chidgey and William H. Hills, Pensacola, Fla.,

assignors to Monsanto Company, St. Louis, Mo., a corporation of DelawareFiled May 31, 1966, Ser. No. 553,890 8 Claims. (Cl. 57-140) ABSTRACT OFTHE DISCLOSURE -A synthetic continuous filament composite singles yarnhaving a high degree of bulk and yet a low degree of stretch isprovided. The yarn has an internal integral uncrirnped load-bearingcentral core of at least one filament surrounded by and having bondedthereto a bulk-imparting sheath made up of a plurality of texturedfilaments.

The present invention relates to a novel continuous filament synthetictextile yarn, to the manner of producing such yarn and to the apparatusemployed therein. It also relates to fabrics produced from such yarn.The yarns of the invention have a high degree of bulk and yet maintain alow degree of stretch. The invention provides a highly integratedprocess for producing the textured yarn of the present invention as wellas an apparatus employed therein and fabrics produced from the novelyarn.

Fabrics woven or knitted from conventional continuous filament yarnspossess a characteristic slick or clammy hand. These fabrics do,however, have superior processability and wearing properties. Fabricsproduced from natural fibers and staple synthetic fibers have adesirable soft hand and high covering power. Fabrics produced from yamscontaining textured continuous synthetic filaments have a desirable softhand but generally possess such a high degree of stretch as to yieldunstable fabrics.

Additionally, since most continuous filament textured yams obtain theirbulkiness from kinks, crimps, curls or other deformation of thefilaments which can be straightened out by tension on the yarn, thebulkiness of such yarns in inversely proportioned to the yarn tension.Fabrics of loose construction, such as most knitted fabrics, can usuallybe formed with the yarn under low tension allowing the crimps or curlsto remain intact. Fabrics of tight construction, however, such as mostwoven fabrics, usually require that the yarn be under higher tensionwhen the fabric is formed. This higher tension straightens out thecrimps or curls and the close construction of the fabric prevents themfrom reforming to any appreciable degree, thereby producing a fabricwith only marginally greater bulkiness than an untextured continuousfilament yarn fabric. Staple fiber yarns, on the other hand, derive themajority of their bulkiness not from crimps or curls but from thediscontinuous nature of the short fibers and from the ends of thoseshort fibers which protrude out from the yarn bundle. It has long been amajor goal in the synthetic fibers industry to provide a yarn composedentirely of continuous filaments possessing the desirable bulkinessretention of staple yarns when used in tightly constructed fabrics whileeliminating the undesirable shedding and pilling associated with yarnsmade from short fibers and eliminating the numerous manufacturing stepsrequired to produce a yarn from staple fibers.

An object of the present invention is to provide a continuous filamentyarn with the desirable soft hand ice and high cover of textured yarnswhile retaining the low stretch properties or longitudinal dimensionalstability of conventional yam.

It is further an object of the present invention to provide an apparatusfor producing the yarn of the invention as well as a highly integratedprocess therefor.

-It is further an object of the present invention to provide knitted orwoven fabrics produced from the novel tension stable yarn.

Other and more specific objects of the invention will become apparentfrom a consideration of the present specification.

The yarn of the present invention is composed entirely of syntheticcontinuous filamentary materials. While the yarn is a composite yarn andis composed only of a plurality of continuous synthetic filaments and isformed from a plurality of yarn ends, the yarn itself is a singles yarnand is to be distinguished from a continuous filament plied yarn. In theinstant specification and claims the term singles yarn is used tospecify a composite yarn which is composed of a plurality of continuousfi1a ments which are united into a compact bundle. The term as useddistinguishes the instant yarn [from ply yarn formed by twistingtogether two or more singles yarns.

The yarn herein is composed of an internal integral core which is itselfmade up of one or more substantially untextured, that is, straight,synthetic continuous filaments. This load-bearing core is surrounded byand has randomly bonded thereto a bulk-imparting sheath made up of aplurality of textured, that is, crinkled, synthetic continuousfilaments. The bonding serves to eliminate movement of the sheath withrespect to the core. It is thus seen that the yarn of the presentinvention, while it is a singles yarn, is a composite yarn in that it ismade up of an integral core of continuous substantially untexturedfilamentary material surrounded by a sheath composed of a plurality oftextured continuous filaments, the sheath being bonded to the core. Theyarn is substantially free of twist but processes into fabric as onehaving 5 or more turns per inch. Preferably the yarn has less than 1turn per inch but may have as high as 5.

It has been previously known in the synthetic textile art to producecontinuous filament synthetic materials possessing a high degree of bulkby texturing a threadline composed of a plurality of continuousfilaments, as for example by subjecting it to a deforming operation,e.g., stutter box crimping or gear crimping. Such yarns, for manypurposes, however, prove to be unsatisfactory in view of the fact thatwhen they are subjected to a moderate degree of tension, the deformationof the individual filaments is removed; and, thus, the high degree ofbulk and covering power of the yarn is eliminated. It is a feature ofthe present invention that a novel high bulk singles yarn is providedwhich is dimensionally stable while being made up completely ofcontinuous filamentary material. When subjected to a tension which isless than the "breaking strength of the core, the inventive yarn retainssubstantially all of the original bulkiness while other textured yarnslose substantially all of their bulk when subjected to only moderateamounts of tension.

In general, the process of the invention involves forwarding asubstantially untextured core yarn which is composed of at least onesynthetic continuous filament to a zone where it contacts a texturedsheath yarn. The textured yarn is composed of a plurality of texturedsynthetic continuous filaments of the same or different chemicalcomposition as the core. The tension on the core in the zone of contactis greater than that on the textured sheath by 0.1 to 5.0 g./d. In anyevent the tension on either is not sufficient to cause substantialbreaking of the filaments. The core filament or filaments and texturedsheath filaments are false twisted together by a false twist means inorder to provide intimate contact between the core and sheath filaments.The textured sheath filaments are bonded to the core filaments. When thebonding is perfected the false twist is released. The bonding may bethermochemical using a solvent for the filaments or may result from theuse of adhesives such as sizes, starch, polyacrylics, etc. The resultingproduct which is a substantially twistless singles yarn is then taken upin an orderly manner by means known in the art with or withoutadditional twist.

The apparatus for producing the yarn of the invention comprises a highlyintegrated combination of elements. Means are provided for forwardingthe core yarn to a zone of contact with a textured sheath yarn under atension in excess of the tension on the sheath. Means for forwardingtextured sheath filaments to the zone of contact with the core yarn arealso provided. False twist means are present to impart a sufiicientdegree of false twist to provide intimate contact between the core andsheath yarns. Binding means are provided for bonding the sheath yarn tothe core yarn as well as means to perfect the bond between the yarns.Finally, means are provided for forwarding the final product yarn to atake-up means where it is taken up in an orderly fashion.

The nature of the present invention will be better understood from thefollowing description taken in connection with the accompanying drawingsin which certain specific embodiments of the instant invention have beenset forth for purposes of illustration.

In the drawings:

FIGURE 1 is a perspective of an apparatus for carrying out the method ofthe present invention to produce the novel yarn.

FIGURE 2 is a schematic representation of the novel yarn of the presentinvention.

FIGURE 3 is a cross sectional view of the yarn of FIGURE 2 taken alongthe longitudinal axis.

Referring now to FIGURE 1 a yarn 1 composed of at least one end ofcontinuous filament synthetic textile filaments is withdrawn from thesupply package 2 and is fed through a guide 3 to snub pin 4. Thesynthetic textile material supplied from supply package 2 may be any ofthe well known synthetic continuous fiber forming materials useful inthe formation of textile fabrics and formed by known techniques fromsynthetic fiber forming thermoplastic resins. Examples of such resinsare polyethylene; polypropylene; polyurethanes; copolymers of vinylacetate and vinyl chloride; the copolymers of vinylidene chloride and aminor proportion of mono-olefinic compound copolrnerized therewith, suchas, for example, vinyl chloride; homopolymers of acrylonitrile,copolymers of acrylonitrile and a minor proportion of at least onemono-olefinic compound copolymerized therewith and polymer blendscontaining combined acrylonitrile in a major proportion; copolymers ofvinyl chloride and acrylonitrile; linear polyesters of aromaticdicarboxylic acids and dihydric compounds, such as polyethyleneterephthalate and copolymers derived from terephthalic acid andbis-1,4(hydroxymethyl) cyclohexane; modifications of such polyesters;linear polycarbonamides such as for example, polyhexamethyleneadipamide; polyhexamethylene sebacamide, polmericmonoamino-monocarboxylic acids, such as polymeric 6-amino caproic acid;and other fiber-forming polymers. The invention is applicableparticularly but not exclusively for treatment of yarns of polyamideshaving recurring intralinear carbonamide groups as an integral part ofthe main molecular chain, generally referred to as nylon yarns.

The yarn supplied from the supply package 2 can be yarn, the filamentsof which have a circular or non-circular cross section. Of particularnote in regard to a noncircular cross sectional filament is one having atriskelion cross section along its length. This type of filament has 3branches, each of which is preferably equally spaced about the centerthereof. The distal ends of the branches are substantially uniformlycurved or bent in one direction. The filament is particularlycharacterized by having threefold axial symmetry and presenting noplanar symmetry. Additionally, other non-circular cross section yarnscan also be employed.

The yarn supplied from package 2 will form the internal core of theproduct. FIGURE 1 illustrates an embodiment of the present inventionwherein a single yarn end composed of a plurality of continuousfilaments is supplied which will form the load-bearing core. It is,however, to be understood that the present invention is not limited to ayarn in which the core is formed from only a single yarn end. One canutilize two or more yarn ends to form the core of the novel yarn. Inview of the fact that the core will serve to provide the longitudinaldimensional stability to the ultimate yarn and will affect the hand aswell as the flexibility of the yarn product, it is necessary that thematerials forming the core, the number of yarn ends making up the core,and the total denier of the core be selected with the desired attributesof the ultimately produced product, i.e., the necessary stability of theyarn itself, in mind. The number of filaments in the core strand and thedenier per filament can vary over a rather wide range, depending uponthe desired properties of the final product yarn. It is preferable thatthe core make up approximately 33% of the total denier of the final yarnproduct since a more balanced product will result between dimensionalstability and bulk. This percentage will vary, however, with the desiredcharacteristics of the final product from about 1050%. In this regard itmay generally be said that where the percentage of the core is greater,there will be less bulk in the ultimatelv produced composite yarn.

The core yarn is forwarded through guide 3 and around the tensioningsnub pin 4 to the core yarn feed roll 5 with its associated separatorroll 6. In the embodiment of FIG. 1, the core yarn normally will bedrawn to provide desired molecular orientation during the process; and,therefore, it is necessary to provide a sufficient number of wraps aboutthe feed roll 5 and its associated separator roll 6 in order to preventor minimize slippage during this drawing of the core. FIG. 1 illustratesa single stage drawing of the core yarn at draw pin 7. It is to beunderstood that the drawing can be accomplished in a plurality of stagesin a manner known in the art or in the alternative all the drawing canbe accomplished prior to the yarns employed in the present procedure.

From the feed roll 5 the core yarn is forwarded to a zone of contactwith a textured yarn. In the presently illustrated embodiment this zoneof contact is in the yarn path just below guide 8, 8a and splitter pin10. The textured and core yarns are false twisted together and thetextured yarn will be randomly bonded to the core. It is necessary,therefore, to provide means for accomplishing this bonding.

In FIG. 1 the bonding means illustrated is a solvent applicator 9 inwhich the yarn is passed in contact with a wick saturated with a solventfor the yarn material. From feed roll 5 the yarn is passed to a draw pin7 to a guide pin 8 and eye guide 80 and to the solvent applicator 9. Itis not necessary that a solvent be applied to the yarn by theapplicator. An adhesive composition can be employed which will serve tobond the textured sheath yarn to the core. It should be noticed thatwhen selecting an adhesive to serve as the bonding agent, considerationmust be given to the appearance of the yarn product as well as thedyeing characteristics, that is, the bonding agent for most purposesshould not impart an unsightly appearance or adversely afi'ect the evendyeing of the product. Also the agent ought not render the product toorigid. These considerations are of course in addition to the basicconsiderations of obtaining a strong bond between the sheath and coreyarns and of employing a bonding agent which will not he unduly tackywhen the product yarn is taken up.

The bonding of the substantially straight cores filamentary yarn to thecrinkly sheath filamentary yarn is preferably a thermochemical one. Thechemical solvents employed in the thermochemical bonding are active soas to soften the yarn and to render the same stickable at the elevatedtemperatures employed. The solvents can be composed of an activesubstance normally solid at room temperature but readily dissolvable ina relatively inert volatile diluent to form a single phase liquid. Whenthe yarn carrying the solvent is heated, the diluent flashes therefromand the action of the active substance is dissipated. Specific solventswill be selected with regard to the type of yarns being procesed.

For treating nylon yarns, solutions of multi-hydroxybenzenes have beenfound to be effective evanescent solvents. Dihydroxybenzene compoundswhich can be employed as the active substance in the solvents includeresorcinol hydroquinone, and pyrocatechol. A trihydroxybenzene, forexample, is pyrogallol. The multi-hydroxybenzenes are not limited to theforegoing specific compounds since derivatives thereof can also be usedto effect cohesion and the stabilization of the yarn. The preferredprocedure is to dissolve the compounds in a suitable inert diluent.Dihydroxybenzenes and trihydroxybenzenes are readily soluble in water,common alcohols (methanol, ethanol, etc.) and common ethers (dimethylether, diethyl ether, etc.). It has been found that a preferredprocedure involves dissolving a predetermined amount of the benzenecompound in water or methanol. An aqueous or methanolic solutioncontaining about 5-80 percent dihydroxybenzene or trihydroxybenzene on aweight basis gives good results. The preferred concentration is -40weight percent. The concentration of the active substance in theevanescent solvent will depend on many factors, such as thecharacteristics of the particular substance employed, the amount ofliquid placed on the nylon yarn, the polymeric structure of the yarns,etc.

Another effective evanescent solvent for use in treating nylon yarns ismolten chloral hydrate or a solution thereof. Chloral hydrate is alsoreadily soluble in water, common alcohols (methanol, ethanol, etc.) andcommon ethers (dimethyl ether, diethyl ether, etc.). A preferredprocedure involves dissolving a predetermined amount of chloral hydratein water or methanol. An aqueous or methanolic solution containing about25-90 weight percent chloral hydrate gives good results. The preferredconcentration of chloral hydrate in solution is -85 weight percent.

For treating acrylic filament yarns (yarns made from acrylonitrilepolymers) solutions of aliphatic cyclic carbonates are effectiveevanescent solvents. These carbonates can be selected from the group ofthe cyclic carbonates of 1,2-; 2.3-; and 1,3-dihydric aliphaticalcohols. Such aliphatic cyclic carbonates include ethylene carbonate,propylene carbonate, trimethylene carbonate, 1,2-butylene I carbonate,1,3-butylene carbonate, 2,3- butylene carbonate, isobutylene carbonateand mixtures thereof. Especially useful of the foregoing group isethylene carbonate. An aqueous solution containing about 5-80 percentaliphatic cyclic carbonate on a weight basis gives good results. Thepreferred cncentration of aliphatic cyclic carbonate is 40-60 weightpercent.

Other bonding techniques can be employed. For example, there may bementioned a process of gas activated bonding of polyamides as describedin US. patent application S.N. 528,699, filed Feb. 16, 1966, havingcommon ownership herewith. Such procedure involves bonding two or morepolyamide structures crossed and under tension at their intersections byexposure to an activator such as a gaseous hydrogen halide or borontrifluoride followed by removal of the activating gas.

In the embodiment of FIG. 1 the solvent is applied from the applicatorprior to the contact with the textured yarn. The core yarn with thesolvent applied then passes to the splitter pin 10 below which it iscombined with the textured yarn in a manner disclosed below. If desired,the solvent can be applied to the yarns below the zone of contact andwhile they are false twisted together.

From the supply packages 11 yarn ends 12 which are composed of aplurality of continuous filaments and which are to serve as the texturedsheath are withdrawn. FIG. 1 illustrates an embodiment of the presentinvention utilizing two ends of yarn serving as the textured or crinkledyarn sheath. It is, however, to be understood that only one yarn end maybe employed or several ends may be utilized. The desired characteristicsof the final product yarn will govern the choice of the number of endsof yarn employed as the textured yarn, as well as the denier of the yarnemployed. It is to be noted here that the material employed as thetextured yarn supply may be the same or different from that yarnemployed in the core and it may be the same or different denier and/ ordenier per filament as the yarn employed as the core material. It isalso within the present concept to employ a mixture of materials withinthe textured sheath and the core. For example, when employing two endsof yarn for the textured yarn supply, they need not be the samematerial, or the same total denier, or the same denier per filament. Theproperties of the final product yarn can be controlled by altering thesevariables. A factor governing the choice of the material, total denierand denier per filament will be the dyeing characteristics desired inthe ultimately produced fabric product. The desired hand of the productfabric is also a factor.

It is preferred that the amount of textured yarn employed be sufficientto make up about 50-75% of the total denier of the ultimately producedproduct. It is also preferred that in order to obtain the optimumoperating conditions in processing, the core yarn and the textured yarnpossess about the same denier per filament. This results in a morebalanced yarn product and more favorable operating conditions during theprocessing to produce the ultimately desired novel yarn. As indicated,the desired hand of the final product will govern to a great extent theamounts and the denier per filament of the textured yarn source.Generally, as one increases the percent of the textured yarn in theproduct, the hand of the final product will be softer. Also the finerthe individual filaments of the textured yarn the softer will be thehand. By varying the denier per filament of the textured yarn source, itis possible to control the appearance of the ultimately produced yarnand the nature of the fabrics produced therefrom. These fabrics can bevaried from cotton-like to woolen-like materials.

The yarns 12 are forwarded through a guide 13 to snub pin 14. After oneor more wraps are taken about snub pin 14, the yarns are forwarded tofeed roll 15 and its asociated separator roll 16 where a sufiicientnumber of wraps are made in order to minimize slippage.

The yarns 12 are then forwarded to a texturing zone. The texturingoperation employed can be any of those texturing means commonly employedwith thermoplastic synthetic fiber materials. There may be mentioned inthis regard a stulfer box, a knife edge, etc., as well as a false twisttexturing means.

A particularly suitable texturing operation is the gear crimpingoperation illustrated in FIGURE 1. In this operation the yarns 12 areforwarded to a positively heated draw pin 17 where they are passed asuflicient number of wraps in order to heat the yarns. The yarns arethen forwarded between the cooled gears 18 traveling at a speed inexcess of the speed of the forwarding roll 15. The yarns are thus drawnbetween the pin 17 and the gears. In the passagethrough the gears thefilaments are deformed and the deformation is set in order to provide rthe necessary texturing. The gears 18 may be positively cooled, but suchpositive cooling is not necessary to obtain a desired texturing at lowspeeds. In addition, multiple passes through the gears 18 may be made inorder to increase the degree of texturing achieved. Such texturingoperation per se is known in the art, and in this respect attention isdirected to US. Patent 3,027,516.

While substantial economic advantages are achieved by having anintegrated process wherein the texturing of the supply yarns 12 isconducted as an integral step of the process, it will be apparent thatit is possible to perform the texturing operation as a separateoperation and simply supply previously textured yarn from a supplypackage directly into the zone of contact with the core yarn. Thispermits omitting the texturing operation per se as a part of the processand apparatus.

The textured yarn is fed from the texturing zone to a point below thesplitter pin where it is combined with the core yarn 1. The core yarnhas been treated in a manner to admit bonding to the textured yarn bythe bonding applicator 9. As previously indicated the bonding treatmentcan be effected subsequent to the combining of the core and texturedyarns if desired.

The textured yarn is fed to the zone of contact with the core yarn undera tension which is less than the tension on the core yarn. In the aspectof the invention where the core yarn is drawn during formation of theproduct the tension on the core will of course be that required for thedrawing of the particular material of the core.

The textured yarn is overfed to the zone of contact with the core yarn.By overfeeding the textured yarn it is meant that the length of thetextured yarn (when considered in a straightened condition) which is fedinto contact with the core yarn in a given amount of time is greaterthan the length of core yarn fed to the contact in the same amount oftime. The amount of overfeed is controlled by adjusting the speed of thetextured yarn feeding means with respect to the speed of the yarnforwarding means below the zone of contact between the textured and coreyarns.

The amount of overfeed of the textured yarn may conveniently bedetermined by relating the total denier of the final product singlesyarn to deniers of the core and textured yarns respectively which makeup that product. In this respect, a given final product yarn will have aspecific total denier T A portion of this total denier will be due tothe denier of the core. Since the core is untextured and the nature ofthe starting materials and draw ratios will be known, the portion of thetotal denier which the core makes up will be a known value C The denierof the textured sheath yarn contained in the final product may then becalculated:

The difference between the total denier of the textured sheath yarn, Sand the denier of the drawn but untextured sheath yarn, U may then bedetermined, i.e., S U This difference between the actual total denier ofthe sheath in the final product and the denier of the drawn butuntextured sheath yarn when divided by the value of the denier for thedrawn but untextured yarn and multiplied by 100 will give the value forthe percent overfeed. Thus:

n U1 U Percent; overfeed= X 100 8 to about 40%. A preferred range ofoverfeed with this type of texturing is about to about overfeed. Whenthe overfeed is below about 8%, insufficient loftiness of the finalproduct is obtained. At an overfeed of above about with the gear crimpedyarn, processing difficulties are encountered; and taking up theoverfeed in order to form a satisfactory coherent final product becomesdifficult. When employing a false twist textured yarn as the sheath anoverfeed of as much as up to about 100% can be employed to yield anacceptable product.

The core and textured yarns are false twisted by false twist impartingmeans 19. Any false twist mechanism capable of imparting'a false twistof from about 5 to about turns per inch in the yarn is satisfactory. Inthis regard there may be mentioned in the friction type false twister,as well as the positive spindle type. A preferred false twist device isdisclosed in US. application S.N. 399,742, filed Sept. 28, 1964, andcomprises interleaved spaced discs rotated in the same direction. Theyarn is twisted with such device by engaging the peripheral edges of theinterleaved discs.

The false twist imparted to the yarn backs up beyond the heated block 20to the splitter pin 10. As a result of the false twisting intimatecontact is provided between the textured yarn and the straight core.While in intimate contact, the bonding between the sheath and core yarnsis perfected. In the illustrated embodiment a bonding composition isemployed which is a solvent for the core yarn. As the yarns progressthrough the heater block 20, the solvent flashes off; and the bondbetween textured yarn and the core yarn is completed. The amount oftwist, as previously indicated, will vary in an amount of from about 5to about 75 turns per inch. The degree of imparted twist will affect theloftiness of the yarn product. With more twist one obtains a tighterbond between the textured yarn and the untextured core and the less loftwill exist in the final product. However, the twist must be a sufficientamount to obtain a unitary final product. That is to say, the finalproduct must be one in which the core and the textured yarn form asingles yarn which does not separate when processed into fabrics.

The amount of twist imparted by the false twist means will control theamount of the overfeed of the textured yarn. In the event, however, thatthe overfeed of the textured yarn to the core is excessive for theparticular type of textured yarn employed, if is necessary in order totake up this degree of overfeed, to apply such a great amount of twistthat a substantial risk is taken that the core will be broken. Inpractice, therefore, it is necessary to determine the optimum conditionsdepending upon the particular types of yarn employed and the particulartype of product desired.

In the embodiment of FIGURE 1, with respect to the zone in which thefalse twist occurs, it is to be noted that the core yarn is drawn fororientation between snubbing pin 7 and draw and take-off rolls 21 withits associated separator roll 22. The draw ratio employed for the coreyarn will vary with the material employed. The degree of draw willaffect the stability provided the product by the core yarn. In generalwith nylon material the draw ratio may be said to be from about 2 toabout 4. This draw ratio will likewise be determined in those caseswhere the drawing is accomplished as a separate step prior to combiningthe core and sheath yarns.

In one aspect of the instant invention it is possible to reduce theamount of drawing of the core yarn accomplished due to the difference inforwarding speed of the yarn between feed roll 5 and draw and take-offroll 21 to a value lower than that indicated above. The false twistingoperation is then permitted to accomplish a portion of the drawing. Thefalse twisting of the core will produce a shortening of the yarn lengthbetween the false twist spindle and the snubbing pin 7 thusaccomplishing a portion of the drawing of the core yarn. This has adisadvantage in that it is difiicult to control the specific amount ofdrawing accomplished by the false twist mechanism and a tendency isencountered to impart uneven dyeing properties to the core as a resultof an uneven drawing. Also there is a tendency where this degree offalse twist is employed to impart a texturing to the core which reducesthe longitudinal stability of the ultimately produced yarn product.

Below the false twist means .19 the false twist imparted to the yarn isreleased so that the product emitted from the false twist spindle is azero twist singles yarn. The product is forwarded from the false twisterto the draw and take-off roll 21 with its associated separator roll 22where a sufiicient number of wraps are provided in order to preventslippage. The draw and take-off roll is operated at a speed in excess ofthe speed of the feed roll to produce the previously referred to drawingof the core yarn in the desired amount. In those embodiments where thedrawing of the core yarn is accomplished as a separate step, it will beapparent that roll 21 will serve as a forwarding roll and will providethe proper tension and yarn speeds during processing. From the draw andtake-off roll the final yarn product is forwarded to the take-up means23. In FIGURE 1, a cone type take-up is illustrated; however, any typeof take-up may be employed, preferably a cheese or cone type withoutimparting twist to the strand since the take-up of the yarn can beaccomplished faster and thus more economically.

The final product yarn is sufficiently lofty in order to prevent anyproblem of crushing the cheese or cone core even if a shrinkage of theyarn occurs. In one aspect of the present invention a relaxation stageis inserted in the processing procedure between the point at which theyarn leaves draw roll 21 and the point at which it is taken up on atake-up means 23. Any type of relaxation step known in the art may beemployed. As for example, a plural stage heating and relaxing proceduresuch as is employed in the relaxation of nylon-66 yarns can be used.

The yarn produced as the final product in the described process is thuscomposed entirely of continuous filaments. It is a singles yarn oflittle or no twist and one which possesses a high degree of bulk and yetretains the longitudinal stability necessary in producing stablefabrics. The yarn is characterized by having .an internal integral coreof a substantially untextured filamentary material which is surroundedby and has bonded thereto a sheath of textured filamentary materials. Bysubstantially untextured is meant that the core is not sufiicientlydeformed so that it fails to provide longitudinal stability to theproduct thus permitting the application of relatively low tensions topull out a large amount of the bulkiness of the product yarn.

A section of the yarn of the present invention is represented by FIGURE2. The textured yarn 31 forms a sheath which is bonded to and surroundsthe core 32. FIGURE 3 is a cross-sectional view of the yarn of FIG- URE2 taken along the longitudinal axis. This view illustrates the internalintegral core 32 surrounded by the textured yarn sheath 31 which isbonded to the core.

The following examples are presented as being illustrative of thepresent invention. These are not to be taken as being lirnitative of theinvention. Changes can, of course, be made therein without departingfrom the spirit of the invention.

Example 1 Employing an apparatus substantially as shown in FIG- URE 1,and in the manner described in the instant specification composite, .acore and textured singles yarn product was produced. The yarn serving asthe core was one end of nylon-66 yarn having an undrawn denier of 700and 68 filaments. The textured yarn was made up of two ends of nylon-66yarn also having an undrawn denier of 700 and 68 filaments. Duringprocessing the draw ratio for the core yarn was estimated to be 3.2 andthe draw ratio for the textured yarn was estimated to be 3.5 with somedrawing occurring during false twisting. The solvent applicator wassupplied with chloral hydrate dissolved in methanol. The weight percentof chloral hydrate in solution was 80. The yarn picked up about 2 weightpercent of the solution. A hot draw pin was used for the making of thetextured yarn and was maintained at a temperature of 210 C. The texturedyarn made from the two ends was fed from the texturing gears to the zoneof contact with the untextured core yarn at an overfeed of 18.8% withrespect to the speed of the core yarn. A false twister as disclosed inS.N. 399,742 mentioned supra was employed and run at a speed of 5100revolutions per minute (r.p.m.), imparting a twist in the compositestrand of t.p.i. The temperature of the heater block was maintained at245 C.

The product yarn was taken up at a speed of 300 yards per minute at awind-up tension of to grams as a cheese package.

The product yarn was a composite singles yarn of substantially no twisthaving an internal integral core surrounded by and having bonded to it asheath of textured yarn. The yarn demonstrated good longitudinalstability and retains its bulkiness when subjected to highlongitudinally applied tension. The final product denier was 650. Theyarn had a boiling water shrinkage of 7.3% and an elongation at break of20.7%.

The yarn was employed in the production of various types of fabricsrequiring a textured yarn of good dimensional stability in the mannerdescribed in subsequent examples herein.

Example 11 The procedure of the above was repeated except an aqueoussolution containing 50 weight percent resorcinol was used instead ofchloral hydrate. The nylon-66 untextured yarn picks up about 1 weightpercent of the solution. The textured continuous filament sheath coheredsatisfactorily to the core of the continuous filament yarn so that itcould be used as filling in the weaving of taffeta yarn without beingtwisted. The load bearing core and the bulk-imparting sheath of thecomposite product caused it to be similar to cotton yarn both inappearance and tactile qualities, as well as'in process handling.

Similarly excellent results are obtained when a methanolic solution of65.5 weight percent resorcinol; an an ethanolic solution of 29.9 weightpercent hydroquinone; a methanolic solution of 26.4 weight percenthydroquinone; saturated aqueous solution of resorcinol; saturatedmethanolic solution of pyrogallol, and the like are employed in theproduction of the untwisted dimensionally stable bulky yarn herein. Ineach case the yarn is composed of a straight load-bearing continuousfilament core and a crimpy bulk-imparting sheath of continuousfilaments. Other nylons such as nylon-6 can be treated with likeresults. In addition, acrylic filament yarn can be processed with theapplication of an .aqueous solution of ethylene carbonate or the like.

Example 111 The procedure of Example I was repeated except the twistimparted by the false twist device to the yarn was increased to turnsper inch. The yarn exhibited less bulk but had increased longitudinaldimensional stability.

Example IV The procedure of Example I was repeated except that only oneend of textured yarn was employed. The yarn showed less bulk. However,the yarn could be converted into woven fabric having a cotton-likeappearance and hand.

Example V The procedure of Example I was repeated except that the coreyarn was made from polyethylene terephthalate polymer. The yarn could beconverted into woven fabric having a cotton-like appearance and hand.

Various deniers of nylon-66 continuous filament yarns were made andprocessed in accordance with Example I to produce the yarns used inmaking'the fabrics in the nine following examples (Examples VI throughXIV). In each case two ends were textured and one end was untextured.

Example VI Example VII A high-sley faille taffeta fabric was woven on aDraper loom using 96 ends/inch of standard 70-34 nylon-66 in the warpwith 50 picks/inch of filling comprised of 290 denier-1'02 filamentsnylon-66 yarn of the invention. The finished fabric had a smooth softhand and a fiat sheet that made it particularly suitable for outerweargarments such as jackets and raincoats.

Example VIII Three ends of 290 denier-102 nylon-66 filament highbulklow-stretch yarn of the invention were plied to form a single end of 870denier yarn. This yarn was skein-dyed conventionally and was used toproduce a single-knit, bulky knit sweater fabric on a Universal V bedflat knitting machine. Knitting efficiency of this yarn proved to besignificantly superior to that of standard spun staple yarns. The fabrichad a very bulky texture and soft, warm hand similar to wool. Sweatersmade of this fabric had a luxurious appearance and were reported to bevery comfortable to the wearer.

Example IX A birdseye Weave crepe fabric was woven on a Draper loom with100 ends/inch warp and 66 picks/inch of filling. Both the warp andfilling yarn were comprised of 115 denier-62 filament nylon 66 yarn ofthe invention that was made by combining two ends of textured 30-26nylon with one' end of untextured 30-10 nylon yarn. The fabric had acharacteristic bulkiness and soft hand that made it suitable for diapersand other skin-contacting applications, as Well as for outerwearapparel.

Example X Yarn similar to that referred to in Example IX was used with aDraper X-3 loom to weave another crepe fabric having 68 ends/inch in thewarp and 70 picks/inch in the filling. Dyed pale blue the finishedfabric had a very soft but dry hand and, when made into dresses andblouses, was observed to show excellent drape about the figure of thewearer.

Example XI Fabric of plain basket weave construction was woven on aCrompton & Knowles S6 loom. The acrylic Warp was comprised of 12 ones,single ply, of a 50:50 mixture of denier and 8 denier Acrilan acrylicfibers of 2 /2 staple length, and 13 t.p.i., of Z twist. Filling was 290denier-102 nylon-66 filament high-bulk low-stretch yarn of theinvention. There were 56 ends/inch in the warp and 56 picks/inch in thefilling. Dyed charcoal grey, the finished fabric had excellent body andsoft handle making it highly attractive for use in trousers and mens andwomens suitings, as well as in winter sport shirts.

Example XII The same yarns and loom referred to in Example XI were againused with 56 ends and 56 picks but in a 2/2 twill fabric construction.This finished fabric had a more dense bulkiness and a mildly harshhandle or hard finish, making it especially suitable for trousers andwomens skirts.

Example XIII A 199 denier-51 filament yarn was made according to theinvention by combining two ends of textured 17 nylon-66 with one end ofuntextured -17 nylon-66 yarn. This bulky dimensional-stable yarn wasused to produce a lightweight, double-knit fabric on a Bentley, 18 cut,double-knit, circular knitting machine. The finished fabric was highlyopaque and had a mildly dry hand. It was judged to be well suited tosuch diverse applications as dresses, bathing suits, slacks, and womenscoat-suits.

Example XIV A warp yarn was formed by plying two ends of regular -13Superloft false twist textured nylon yarn; 132 ends/inch of this yarnwas used with 64 picks/inch of a filling yarn comprised of 290denier-102 filament nylon-66 yarn of the invention. These yarns wereused in a Tricotine construction woven on a Crompton & Knowles W-3 broadloom. Dyed dark brown, this fabric had a pleasant dry hand, highopacity, bulky body, practically no stretch in the filling direction butexcellent stretch and recovery in the warp direction. Made up in stretchpants this fabric was observed to show excellent drape and hugging tothe contours of the wearer (but without the uncomfortable clingingsometimes noted with stretch fabrics).

Example XV Drawn nylon-66 continuous filament yarn having a total denierof 70 and 34 individual filaments was textured by passing it through aconventional commercial stuffer box crimper. This yarn was fed acrossthe heater to the false twist device of the apparatus herein described.Just prior to contacting the textured yarn, a drawn 70/34 nylon-66untextured yarn was coated with the chloral hydrate so lution of ExampleI. The contacting ends were falsetwisted 35 t.p.i. The yarn was taken upon a coner. The yarn could be converted into woven fabric having acotton-like appearance and hand.

Yarns of the invention are high-1y versatile in end usage and can bewoven on any of the conventional textile looms or be knitted on any typeof conventional knitting machines for use in sweaters, skirts, dresses,blouses, rainwear, and other outerwear garments, sheets etc. Incombination with other fibers, yarns of the invention are useful for skipants and sportswear, suitings, etc. In general, the yarns may beapplied to most end uses in which the more desirable inherent propertiesof regular nylon are required but without the harsh hand characteristicof regular nylon. Fabrics made from yarns herein are more resistant tomussing, that is, garments therefrom worn by a consumer after being in asitting position for an extended time will show less crumple or rufile.Moreover, any unussing will disappear more rapidly upon the wearerr1s1ng.

Since many different embodiments of the invention can be made withoutdeparting from the spirit and scope thereof the invention is not limitedby the specific illustrations except to the extent defined in thefollowing claims.

What is claimed is:

1. A synthetic continuous filament composite singles yarn having oneinternal integral substantially uncrimped load-bearing central corecomposed of at least one synthetic continuous filament, said core beingsubstantially completely surrounded by and having bonded thereto abulk-imparting continuous sheath made up of a plurality of texturedsynthetic continuous filaments.

2. A singles yarn as in claim 1, wherein the core constitutes from about10 to about 50% of the total denier of the yarn.

3. A singles yarn as in claim 1, wherein the textured yarn sheath issolvent bonded to the core.

4. A singles yarn as in claim 1, wherein the synthetic filament materialof the core is of a difierent chemical composition from that of thetextured yarn sheath.

5. A singles yarn as in claim 4, wherein the core is composed ofcontinuous filaments of polyethylene terephthalate and the texturedsheath is composed of continuous filaments of a polyamide havingrecurring intra-linear carbonarnide groups as an integral part of themain molecular chain.

6. A singles yarn of claim 1 composed entirely of polyhexamethyleneadipamide.

7. A singles yarn as in claim 1, wherein the textured sheath yarn is agear crimped yarn.

8. A fabric containing a singles yarn of claim 1.

References Cited UNITED STATES PATENTS 2/1945 Heymann 57140 11/1962Bloch 57-14O 11/ 1963 Boyer 5714O 6/1964 Fairley et a1 5714() 9/1965Hall et al 57140 XR 12/1965 Joly 57-140 XR FOREIGN PATENTS 2/1963Canada.

11/ 1937 Great Britain.

STANLEY N. GILREATH, Primary Examiner.

WERNER SCHROEDER, Assistant Examiner.

